document.getElementsByClassName = function (els, class_name) {var ret_obj = new Array();var j = 0;for(var i=0; i < els.length; i++) {if(els[i].className) {classes = els[i].className.split(' ');for(x=0; x < classes.length; x++) {if(classes[x] == class_name) ret_obj[j++] = els[i];}}}return ret_obj;}